diff --git a/Source/d_io.h b/Source/d_io.h
index 7932f309..1f0f58bd 100644
--- a/Source/d_io.h
+++ b/Source/d_io.h
@@ -21,6 +21,13 @@
 #ifndef D_IO_INCLUDED
 #define D_IO_INCLUDED
 
+#ifndef TRUE
+  #define TRUE true
+#endif
+#ifndef FALSE
+  #define FALSE false
+#endif
+
 #ifdef _MSC_VER
   #include <direct.h>
   #include <io.h>
@@ -28,13 +35,28 @@
   #define W_OK 2
   #define R_OK 4
   #define S_ISDIR(x) (((sbuf.st_mode & S_IFDIR)==S_IFDIR)?1:0)
-  #define TRUE true
-  #define FALSE false
   #define strcasecmp _stricmp
   #define strncasecmp _strnicmp
   #ifndef PATH_MAX
      #define PATH_MAX _MAX_PATH
   #endif
+#elif defined (__unix__)
+  #include <unistd.h>
+  #include <ctype.h> // tolower()
+  #ifndef O_BINARY
+    #define O_BINARY 0
+  #endif
+  #define stricmp strcasecmp
+  #define strnicmp strncasecmp
+  static inline char *strlwr (char *str) {
+    char *c = str;
+    while (*str != '\0')
+    {
+        *str = tolower (*str);
+        str++;
+    }
+    return c;
+  }
 #else
 #include <unistd.h>
 #endif
diff --git a/Source/d_main.c b/Source/d_main.c
index 92cb899d..f316c609 100644
--- a/Source/d_main.c
+++ b/Source/d_main.c
@@ -1263,6 +1263,7 @@ void D_DoomMain(void)
   if (devparm)
     printf(D_DEVSTR);
 
+#ifndef __unix__
   if (M_CheckParm("-cdrom"))
     {
       printf(D_CDROM);
@@ -1275,6 +1276,7 @@ void D_DoomMain(void)
       // killough 10/98:
       sprintf(basedefault, "c:/doomdata/%s.cfg", D_DoomExeName());
     }
+#endif
 
   // turbo option
   if ((p=M_CheckParm ("-turbo")))
diff --git a/Source/g_game.c b/Source/g_game.c
index b917dff1..caa6b3e8 100644
--- a/Source/g_game.c
+++ b/Source/g_game.c
@@ -1156,9 +1156,11 @@ void G_SaveGameName(char *name, int slot)
   // Ty 05/04/98 - use savegamename variable (see d_deh.c)
   // killough 12/98: add .7 to truncate savegamename
 
+#ifndef __unix__
   if (M_CheckParm("-cdrom"))
     sprintf(name, "c:/doomdata/%.7s%d.dsg", savegamename, slot);
   else
+#endif
     sprintf(name, "%s/%.7s%d.dsg", basesavegame, savegamename, slot);
 }
 
diff --git a/Source/i_system.c b/Source/i_system.c
index 55977dd8..d37cfe39 100644
--- a/Source/i_system.c
+++ b/Source/i_system.c
@@ -257,7 +257,7 @@ void I_Quit (void)
       G_CheckDemoStatus();
    M_SaveDefaults();
 
-#if defined(MY_SDL_VER)
+#if defined(MY_SDL_VER) && defined(_MSC_VER)
    // Under Visual C++, the console window likes to rudely slam
    // shut -- this can stop it
    if(*errmsg || waitAtExit)
diff --git a/Source/m_fixed.h b/Source/m_fixed.h
index c80643bc..8bae7313 100644
--- a/Source/m_fixed.h
+++ b/Source/m_fixed.h
@@ -36,6 +36,7 @@
 #define __attribute__(x)
 #endif
 
+#include <stdlib.h> // abs()
 #include "i_system.h"
 
 //
diff --git a/Source/p_mobj.c b/Source/p_mobj.c
index a674db75..efed3266 100644
--- a/Source/p_mobj.c
+++ b/Source/p_mobj.c
@@ -717,8 +717,8 @@ mobj_t *P_SpawnMobj(fixed_t x, fixed_t y, fixed_t z, mobjtype_t type)
   return mobj;
 }
 
-static mapthing_t itemrespawnque[ITEMQUESIZE];
-static int itemrespawntime[ITEMQUESIZE];
+mapthing_t itemrespawnque[ITEMQUESIZE];
+int itemrespawntime[ITEMQUESIZE];
 int iquehead, iquetail;
 
 //
diff --git a/Source/r_segs.c b/Source/r_segs.c
index 8b53b218..03a090b9 100644
--- a/Source/r_segs.c
+++ b/Source/r_segs.c
@@ -45,9 +45,9 @@ rcsid[] = "$Id: r_segs.c,v 1.16 1998/05/03 23:02:01 killough Exp $";
 // killough 1/6/98: replaced globals with statics where appropriate
 
 // True if any of the segs textures might be visible.
-static boolean  segtextured;
-static boolean  markfloor;      // False if the back side is the same plane.
-static boolean  markceiling;
+boolean  segtextured;
+boolean  markfloor;      // False if the back side is the same plane.
+boolean  markceiling;
 static boolean  maskedtexture;
 static int      toptexture;
 static int      bottomtexture;
@@ -61,8 +61,8 @@ lighttable_t    **walllights;
 //
 // regular wall
 //
-static int      rw_x;
-static int      rw_stopx;
+int      rw_x;
+int      rw_stopx;
 static angle_t  rw_centerangle;
 static fixed_t  rw_offset;
 static fixed_t  rw_scale;
diff --git a/Source/z_zone.h b/Source/z_zone.h
index 2d1eeaf7..a65304dd 100644
--- a/Source/z_zone.h
+++ b/Source/z_zone.h
@@ -99,6 +99,8 @@ void Z_DumpHistory(char *);
 #define calloc(n1,n2)      Z_Calloc(n1,n2,PU_STATIC,0)
 #define strdup(s)          Z_Strdup(s,PU_STATIC,0)
 
+// dprintf() is already declared in <stdio.h>, define it out of the way
+#define dprintf doomprintf
 // Doom-style printf
 void dprintf(const char *, ...) __attribute__((format(printf,1,2)));